Lithographic printing-machine



(No Molel.) 2 Sheets-Sheet 1.

J.. T. HAWKINS.

LITIIoGR/IPHIG PRINTING MACHINE.

No. 385,860. Patented July 10, 1888.

(No Model.)

. f2 Sheets-Sheet 2. J. 'I'.-HAWKINS- LITHOGRAPHIG PRINTING MACHINE.

Patented July 1o, 1888.

N PETERS. Phum-mhngnpner. wmuugmn, D. C.

NITED STATES ATENT OFFICE.

JOHN T. HAVKINS, OF TAUNTON, MASSACHUSETTS.

SPECIFICATION forming part of Letters Patent ISO. 385.860, dated July 10, 1888.

Application filed June 2Q, 188:3. Serial No. 169,352. (No model.)

To LZZ whom z'fb nul/ y concern:

Be it known that I, JOHN T. Hawkins, of Taunton, in the county of Bristol and State of Massachusetts, have invented a certain new and useful Improvement in Lithographie Printing-Machines, which invention or improvement is fully set forth and illustrated in the following specilication and accompanying drawings.

The object of this invention may be explained as follows: Lithographie stones are seldom of uniform thicknessthat is, the unfinished bottom of any stone is rarely parallel with the plane of its finished upper printing or form surl'ace. Such being the case, the object of this invention is accomplished by combining with marginal or corner leveling-screwssuch as are usually employed, which, passing down through the margins of the stone-plate, rest on the bed or box of the machine and are operated from above-encor more bush-adj usting screws placed at any desired points under the stone-plate, which pass up from below through the bed or box of the machine, and which may be separately adjusted from below. Thus said marginal leveling-screws proper level the stone to any desired general horizontal plane, and then said adjusting-screws are adjusted to take the set and pressure of the stone-plate. The printing-surface of the stone is thus brought exactly level, regardless of the angle or plane of its under suriace, and at the same time is prevented any necessity for springing the stone-plate by the marginal leveling-screws (thereby endangering the breaking of the stone) by attempting to accurately adjust or set the stone by said leveling-screws alone.

In the drawings, Figure 1 is a longitudinal vertical section through the ordinary form of the bed or box of a lith ographic printing-press,

showing one ofthe new adj usting-screws corr stituting this invention. Fig. 2 is a plan of the same as seen from the under side. Fig. 3 is an enlarged vertical section of one of the central su p porting-screws and a portion of the bcdbox and stoneplate containing the same. Fig. 4 is a plan of part of the face of the stoneplate. Figs. 5 and G show, respectively, views similar to Figs. l and 2, but enlarged and provided with four under adj listing-screws instead of one.

The several parts are indicated by letters as follows: A is the bed or box. B is the stoneplate; O, the stone. D D are the four usual leveling and supporting screws tapped in thc stone-plate B, their points impinging upon the bed. or box A. So far as described this is the usual construction, leaving the central parts of the stone unsupported, except by its own transverse strength.

A bush or sleeve, a, is iitted loosely into a corresponding hole in the stone-plate B and prevented from rotating by a pin, b, inserted in it and running in a groove, c, in the stoneplate B. The stone-plate B may thus be lifted olf from the bush a by the action of the leveling corner-screws D, orso that the bush a may be dropped out of contact at its shoulders with the bottom of the stone-plate B when it is necessary to support it in leveling by the four corner screws only. The sleeve a projects below the bottom of the stone-plate B, and is there enlarged, so as to allow said plate to rest upon the shoulders forming said enlargement. The projecting lower part of said sleeve forms a threaded nut for the entrance of the adj ustingscrew d. Said screw has a collar formed upon it, near its lower end, having its under side of spherical form, as at c, resting upon a correspondingly-formed plate, f, the latter secured to the inside of the bottom of the bed or box A; or a spherical concave surface may be formedon the inside ofthe bottom of the bedbox itself for the reception of the spherical collar on the screw d. The screw d projects through the bottom of the bed or box A, and secured thereto is a bevel-gear, g. The object of making the bottom of the collar cof the adjustingscrew d of a spherical form is to pcrmit said screw to vibrate slightly in its bed f, the hole through the box A, through which the lower part of said screw passes, making a loosel or easy fit with said part of said screw. Carried in suitable brackets, h, is a shaft, t'. On the inner end of shaft t' is a bevel-gear, g, meshing with the gear g. A suitable handwhee1,j, is secured to the other end of shaft i, and a set screw, k, is inserted in the outer bracket, 7L, to secure the shaft t' in any position in which it may be placed.

In the operation ofthe parts the sleeve a is run down out of the way while leveling the stone by means of the corner-screws D. Vhen ICO the leveling is completed, the bush or sleeve a is brought up, by means of the hand-wheel j and the mechanism therewith described, until its shoulder bears against the under side ofand supports the stone-plate B at that point, when it is secured against running back While the machine is in operation by setting up the set screw k, which bites into the shaft i.

I do not confine myself',` to a single central supporting-screw, as shown, as it is obvious that several may be used, if desired; nor do l confine myself to the means shown of rotating the screw d from the bottom and back of the bed, as it is obvious that a Worm-wheel and worm, or ratchet and paWl, or other mechanism, inay be substituted for the bevelgears g g and the shaft z',- but,

Having thus fully described my said improvement, as of my invention I claim- JOHN T. HAWKINs.

Witnesses:

AELIsHA T. JACKSON,

J. F. HALEY. 

